# DB crasher

ThwartedEfforts (abakun@scinc.com)
Tue, 23 Apr 1996 07:27:19 PDT

- Messages sorted by:[ date ][ thread ][ subject ][ author ]

    At 11:48 PM 4/22/96 PDT, manta@dartmouth.edu wrote:
    >As for the clock dying trying to keep up, unless someone added pre-emptive
    >multi-tasking when I wasn't looking, the server can kill ~15,000 tasks per
    >suspend(0).  This ought to be enough to keep up with most fork bombs.

    A certain task can continue killing tasks until either itself timesout or
    needs to suspend.  Since nearly everyone has different task limits these
    days (E_MOO has 100,000 ticks for both foreground and background tasks, and
    7 and 5 seconds respectively), the time between a suspend(0) on your system
    is most likely different than on mine, and I can probally kill many more
    tasks than 15,000.

    In fact, you should be able to keep up with ALL fork bombs since you can set
    the task limit and timeouts in the database and pull some fancy tricks with
    forking off a task killer.  I doubt your "2.2.3 (hacked)" server supports
    anything like this.  Of course, if you had a more recent version, and knew
    it :), you'd be able to set the number of tasks on a per user basis.  Before
    we were able to set upper limits on the number of tasks, someone was going
    to give themselves large timeout values so they would always win in a case
    like that.  It's probally in the archives.  But you should still upgrade.

    For all you server hackers out there:  If you are going to be hacking the
    server, it makes sense to not replace the version number, but append
    something to the version string saying what you have done, a la
    "1.8.0p4 (frobnicator 3.8 enabled)"

    Andy.